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authorRonny Hegewald <ronny.hegewald@online.de>2012-11-27 14:13:39 +0000
committerRonny Hegewald <ronny.hegewald@online.de>2012-11-27 14:13:39 +0000
commitb98cd5c1b5a6f81a4ee3ac76800fa390dc91cea1 (patch)
treeafe87dec3b75af46ca324db8ee210a0c01d5ef51 /tools/libxl/libxl.c
parent3ffb163212caab8b2ce3dbb29fb1ab41219ddfe8 (diff)
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libxl: fix a variable underflow in libxl_wait_for_free_memory
When xl is called to create a domU and there is not enough memory available, then the autoballooning is called to extract memory from dom0. During the ballooning a loop in libxl_wait_for_free_memory() waits unless enough memory is available to create the domU. But because of a variable-underflow the loop can finish too soon and xl finally aborts with the message: xc: error: panic: xc_dom_boot.c:161: xc_dom_boot_mem_init: can't allocate low memory for domain: Out of memory libxl: error: libxl_dom.c:430:libxl__build_pv: xc_dom_boot_mem_init failed: Device or resource busy libxl: error: libxl_create.c:901:domcreate_rebuild_done: cannot (re-)build domain: -3 The variable-underflow happens when freemem_slack is larger then info.free_pages*4, because the solution of this operation is converted implicit to a unsigned int to match the type of memory_kb. Add a extra check for this condition to solve the problem. Signed-off-by: Ronny Hegewald <Ronny.Hegewald@online.de> Acked-by: Ian Campbell <ian.campbell@citrix.com> Committed-by: Ian Campbell <ian.campbell@citrix.com>
Diffstat (limited to 'tools/libxl/libxl.c')
-rw-r--r--tools/libxl/libxl.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index de75ee0f25..6c77556cd5 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -3764,7 +3764,8 @@ int libxl_wait_for_free_memory(libxl_ctx *ctx, uint32_t domid, uint32_t
rc = libxl_get_physinfo(ctx, &info);
if (rc < 0)
goto out;
- if (info.free_pages * 4 - freemem_slack >= memory_kb) {
+ if (info.free_pages * 4 >= freemem_slack &&
+ info.free_pages * 4 - freemem_slack >= memory_kb) {
rc = 0;
goto out;
}